A displayer mainly includes a liquid crystal panel and a backlight module, which applies the physical characteristic of liquid crystals. Its working principle is described as follows: liquid crystal molecules are arranged in order when a voltage is applied thereon, so as to make the light pass through; when no voltage is applied on the liquid crystal molecules, the light is blocked. Because the liquid crystal molecule itself cannot emit light, a backlight module is required so as to achieve the display. The backlight module is characterized in high brightness, long service life and capable of emitting light uniformly.
When an external voltage is applied to the liquid crystal screen, the liquid crystal molecules therein may be rearranged. In order to detect such rearrangement and make it sensible, visible for human eyes or achieve a maximum contrast ratio, it is required to arrange polarizing films at an upper and a lower surface of the liquid crystal screen respectively. In addition, in order to make the optical performance of the backlight module match with the liquid crystal screen so as to achieve a fine image quality, a prism film plate in the backlight module needs to be rotated in a certain angle, so as to prevent the occurrence of oblique stripes in the display image of the liquid crystal panel.
A parameter of the rotation angle of the prism of the backlight module in the related art is generally the empirical parameter used by those skilled in the art, which is acquired by a manual simulation and repeatedly testing the image quality of the liquid crystal module. However, the process hereinabove is complicated and the testing is not accurate enough, and the testing result depends on the vocational levels of those skilled in the art remarkably, which has a great limitation. Therefore, it is an issue needed to be solved how to simulate the rotation angle of the prism in the backlight module.